Laser-driven ion sources for high-brightness high-purity ion beams

Summary form only given. Surface-plasma ion sources are critical to generating high-brightness, high purity ion beams on applied-B ion diodes. The source plasma must meet requirements for species, thickness, purity, degree of conductivity, formation timescale, and feasibility. Laser ionization schemes have been used on high-power ion diodes with encouraging but inconsistent results in diode impedance and beam purity. We are characterizing two laser-driven Li/sup +/ schemes for 100-200 cm/sup 2/ sources: a single 10 ns Nd:YAG pulse at 0.3-1 J/cm/sup 2/, or the 2-laser LEVIS scheme. Recognizing anode surface contamination as a key issue in 10/sup -5/-10/sup -6/ Torr pulsed power vacuum, we subject well-characterized 0.5 /spl mu/m LiAg films on stainless substrates to extended 150-400/spl deg/C heating and plasma discharge sputter cleaning after pumpdown in a test chamber, prior to pulsing the source lasers. A detailed diagnostic set includes absolutely-calibrated, streaked, CCD-imaged spectrographs for plasma properties, 2-color laser deflection for plasma/neutral expansion, ion time-of-flight spectrograph with ionizer for species content, and a tunable narrow-band dye laser for near-resonant absorption.